Sunspots and hip fractures.

In this paper a remarkable statistical link between sunspot cycles and prevalence of hip fractures in the elderly is shown. Hip fractures in old people are due to: 1. increased bone fragility for metabolic bone disease; 2. increased propension to fall. Though it is obvious that a correlation does not imply any causal relationship, reasonable conjectures can be allowed. The hypothesis of an 11-year cyclic variation of ultraviolet radiation as a cause of hip fractures is untenable; one may better assume that solar flares can negatively influence the nervous postural regulation leading to a greater propensity to accidental falls.